Fourspot butterflyfish

The four-spotted butterflyfish or fourspot butterflyfish (Chaetodon quadrimaculatus) is a species of butterflyfish (family Chaetodontidae) found in the Pacific Ocean from the Ryukyus, Ogasawara (Bonin) Islands and Taiwan to the Hawaiian, Marquesan, and Pitcairn islands, south to the Samoan and Austral Islands and the Marianas and Marshall Islands in Micronesia.[1]

Four-spotted butterflyfish
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Actinopterygii
Order:
Perciformes
Family:
Chaetodontidae
Genus:
Chaetodon (but see text)
Subgenus:
Exornator
Species:
C. quadrimaculatus
Binomial name
Chaetodon quadrimaculatus

The fourspot butterflyfish is a marine coralivorous organism. Therefore, its noted geographic distribution, as well as population-level spatial distribution and temporal variation in density, is correlated to relative distributions and abundance of the corals that butterflyfish are dependent on for food.[2]

It is a quite distinct species, but most closely related to the speckled butterflyfish (C. citrinellus). Together they are basal in the subgenus Exornator, and might be intermediate between the core group of this subgenus and the species of the Rhombochaetodon (or Roaops) lineage. If that is correct, the latter would require to be merged into Exornator. If the genus Chaetodon is split up, Exornator might become a subgenus of Lepidochaetodon.[3]

Butterflyfish as a family are a common marine aquarium specimen as a result of their varying colors and patterns, and contribute to 4% of the global fish trade. [4]

Taxonomy

As one of 90 extant species in the genus Chaetodon, the fourspot butterflyfish shares the following characteristics: a laterally compressed body with bilateral symmetry, and ctenoid scales, identified by their comb-like edges.[5] One defining characteristic of this species is its four rounded, eye-shaped spots, two on each lateral surface. These spots are theorized to help this butterflyfish avoid predation by either intimidating predators or diverting attack of predators to potentially less fatal regions of the body.[6]

Diet and feeding

C. quadrimaculatus is an obligate, hard coral feeder, an adaptation that is theorized to have evolved approximately 3.2 million years ago.[7] This species is highly dependent on scleractinian corals, an order of Anthozoa where approximately 50% of species are reef-building zooxanthellate.[8] Butterflyfish typically feed from corals by removing individual polyps while leaving the calcareous skeleton undisturbed.[9] They use a picking method where they grip prey with the tips of their upper and lower anterior jaws.[10] Due to their specialized dependence on corals, C. quadrimaculatus and other obligate corallivorous species have an increased bite rate, pointing to a higher feeding efficiency, than butterflyfish that are facultative corallivores.[11]

Social structure

Owning to their obligate dependence on corals, fourspot butterflyfish tend to be distributed in stable feeding territories with high fidelity for each site and male-dominated defense mechanisms.[12][13] The social structure is dominated by heterosexual, adult pair-bonds, while juveniles are typically solitary. [14][15] However, there have also been observations of homosexual pair bonds and pair bonds between sexually immature butterflyfish in this genus.[16] Therefore, the evolution of pair bonds may offer benefits beyond increasing reproductive fitness.[16] Other proposed advantages of pair-bonding include increased foraging efficiency and vigilance against predators.[11] Within heterosexual pair-bonds, evidence supports the evolution of sex-specific roles rather than mutual territory defense.[17] In this division of labor, males actively defend territory allowing females to successfully forage and therefore increase their fecundity.[13]

Juvenile

Reproduction and development

Fourspot butterfly fish typically reproduce in monogamous pair bonds.[14] They reproduce via spawn breeding where the gonochoristic males and females release their respective gametes into the water column for fertilization.[18] Eggs are typically less than 1 mm in their pelagic form and fertilized eggs hatch in approximately 30 hours.[19] Like other butterfly fish in this family, C. quadrimaculatus has a specialized larval state called tholichthys, where the head is covered by fused plates, giving rise to a distinctive head spination.[19] Although no definitive results have been collected, there is little to minimal or no parental care in this species as a result of their spawn breeding reproductive tactic.[14] After larval development and hatching, juveniles directly settle on coral which offer protection from predators.[20]

Conservation

Since fourspot butterflyfish are highly associated with scleractinian coral, they are an indicator of reef health and their relative abundance is contingent on coral reef abundance.[7] With recent global changes in climate, especially the 2015-2016 rise in water temperatures and mass coral bleaching event in the central Indo-Pacific, this species may have experienced a decrease in food resource. [21][22] Large-scale coral bleaching has also been associated with decreases in both interspecific and intraspecific aggression in butterflyfish.[22] Research in other species of butterflyfish show that local coral bleaching does not have immediate effects on local population abundance of butterflyfish, but does lead to sublethal effects such as decreased growth and reproduction rates.[23]

Footnotes
  1. FishBase [2008]
  2. Pratchett, M. S.; Wilson, S. K.; Berumen, M. L.; McCormick, M. I. (2004-09-01). "Sublethal effects of coral bleaching on an obligate coral feeding butterflyfish". Coral Reefs. 23 (3): 352–356. doi:10.1007/s00338-004-0394-x. ISSN 1432-0975.
  3. Fessler & Westneat (2007), Hsu et al. (2007)
  4. Degidio, Jon-Michael L. A.; Yanong, Roy P. E.; Watson, Craig A.; Ohs, Cortney L.; Cassiano, Eric J.; Barden, Kevin (2017-07-03). "Spawning, Embryology, and Larval Development of the Milletseed Butterflyfish Chaetodon miliaris in the Laboratory". North American Journal of Aquaculture. 79 (3): 205–215. doi:10.1080/15222055.2017.1302025. ISSN 1522-2055.
  5. Thresher, Ronald E., 1949- (1984). Reproduction in reef fishes. Distributed in the U.S. by T.F.H. Publications. ISBN 0-87666-808-2. OCLC 1089502252.CS1 maint: multiple names: authors list (link)
  6. Gagliano, Monica (2008-07-01). "On the spot: the absence of predators reveals eyespot plasticity in a marine fish". Behavioral Ecology. 19 (4): 733–739. doi:10.1093/beheco/arn013. ISSN 1045-2249.
  7. BELLWOOD, D. R.; KLANTEN, S.; COWMAN, P. F.; PRATCHETT, M. S.; KONOW, N.; van HERWERDEN, L. (2010). "Evolutionary history of the butterflyfishes (f: Chaetodontidae) and the rise of coral feeding fishes". Journal of Evolutionary Biology. 23 (2): 335–349. doi:10.1111/j.1420-9101.2009.01904.x. ISSN 1010-061X. PMID 20487131.
  8. Stolarski, Jarosław; Meibom, Anders; Przeniosło, Radosław; Mazur, Maciej (2007-10-05). "A Cretaceous Scleractinian Coral with a Calcitic Skeleton". Science. 318 (5847): 92–94. Bibcode:2007Sci...318...92S. doi:10.1126/science.1149237. ISSN 0036-8075. PMID 17916731.
  9. Pratchett, Morgan S. (2005-08-25). "Dietary overlap among coral-feeding butterflyfishes (Chaetodontidae) at Lizard Island, northern Great Barrier Reef". Marine Biology. 148 (2): 373–382. doi:10.1007/s00227-005-0084-4. ISSN 0025-3162.
  10. Copus, Joshua M.; Gibb, Alice C. (2013-12-01). "A forceful upper jaw facilitates picking-based prey capture: biomechanics of feeding in a butterflyfish, Chaetodon trichrous". Zoology. 116 (6): 336–347. doi:10.1016/j.zool.2013.08.005. ISSN 0944-2006. PMID 24156977.
  11. Gregson, M. A.; Pratchett, M. S.; Berumen, M. L.; Goodman, B. A. (2008-03-28). "Relationships between butterflyfish (Chaetodontidae) feeding rates and coral consumption on the Great Barrier Reef". Coral Reefs. 27 (3): 583–591. Bibcode:2008CorRe..27..583G. doi:10.1007/s00338-008-0366-7. ISSN 0722-4028.
  12. Hourigan, Thomas F. (1989). "Environmental determinants of butterflyfish social systems". Environmental Biology of Fishes. 25 (1–3): 61–78. doi:10.1007/bf00002201. ISSN 0378-1909.
  13. Whiteman, E. A.; Ct, I. M. (2004). "Monogamy in marine fishes". Biological Reviews. 79 (2): 351–375. doi:10.1017/s1464793103006304. ISSN 1464-7931. PMID 15191228.
  14. Pratchett, Morgan S.; Pradjakusuma, Oki. A.; Jones, Geoffrey P. (2006-01-21). "Is there a reproductive basis to solitary living versus pair-formation in coral reef fishes?". Coral Reefs. 25 (1): 85–92. Bibcode:2006CorRe..25...85P. doi:10.1007/s00338-005-0081-6. ISSN 0722-4028.
  15. Roberts, Callum M.; Ormond, Rupert F. G. (1992). "Butterflyfish social behaviour, with special reference to the incidence of territoriality: a review". Environmental Biology of Fishes. 34 (1): 79–93. doi:10.1007/bf00004786. ISSN 0378-1909.
  16. Nowicki, Jessica P.; Walker, Stefan P. W.; Coker, Darren J.; Hoey, Andrew S.; Nicolet, Katia J.; Pratchett, Morgan S. (2018-04-19). "Pair bond endurance promotes cooperative food defense and inhibits conflict in coral reef butterflyfish". Scientific Reports. 8 (1): 6295. Bibcode:2018NatSR...8.6295N. doi:10.1038/s41598-018-24412-0. ISSN 2045-2322. PMID 29674741.
  17. Nowicki, Jessica P.; O’Connell, Lauren A.; Cowman, Peter F.; Walker, Stefan P. W.; Coker, Darren J.; Pratchett, Morgan S. (2018-04-11). "Variation in social systems within Chaetodon butterflyfishes, with special reference to pair bonding". PLOS ONE. 13 (4): e0194465. Bibcode:2018PLoSO..1394465N. doi:10.1371/journal.pone.0194465. ISSN 1932-6203. PMC 5894994. PMID 29641529.
  18. Lobel, Phillip S. (1989), Motta, Philip J. (ed.), The butterflyfishes: success on the coral reef, Developments in environmental biology of fishes, Springer Netherlands, 9, pp. 125–130, doi:10.1007/978-94-009-2325-6_9, ISBN 978-94-010-7545-9 Missing or empty |title= (help); |chapter= ignored (help)
  19. Leis, Jeffrey M. (1989), Motta, Philip J. (ed.), The butterflyfishes: success on the coral reef, Developments in environmental biology of fishes, Springer Netherlands, 9, pp. 87–100, doi:10.1007/978-94-009-2325-6_6, ISBN 978-94-009-2325-6 Missing or empty |title= (help); |chapter= ignored (help)
  20. Pratchett, M. S.; Graham, N. A. J.; Cole, A. J. (2013-03-13). "Specialist corallivores dominate butterflyfish assemblages in coral-dominated reef habitats". Journal of Fish Biology. 82 (4): 1177–1191. doi:10.1111/jfb.12056. ISSN 0022-1112. PMID 23557298.
  21. Lawton, Rebecca J.; Pratchett, Morgan S. (2012-06-05). "Influence of dietary specialization and resource availability on geographical variation in abundance of butterflyfish". Ecology and Evolution. 2 (7): 1347–1361. doi:10.1002/ece3.253. ISSN 2045-7758. PMID 22957144.
  22. Keith, Sally A.; Baird, Andrew H.; Hobbs, Jean-Paul A.; Woolsey, Erika S.; Hoey, Andrew S.; Fadli, N.; Sanders, Nathan J. (2018-10-22). "Synchronous behavioural shifts in reef fishes linked to mass coral bleaching" (PDF). Nature Climate Change. 8 (11): 986–991. Bibcode:2018NatCC...8..986K. doi:10.1038/s41558-018-0314-7. ISSN 1758-678X.
  23. Pratchett, M. S.; Wilson, S. K.; Berumen, M. L.; McCormick, M. I. (2004-08-20). "?Sublethal effects of coral bleaching on an obligate coral feeding butterflyfish?". Coral Reefs. 23 (3): 352–356. doi:10.1007/s00338-004-0394-x. ISSN 0722-4028.
gollark: I wonder if it's still around at home somewhere.
gollark: Amazon. I guess whoever bought it didn't notice which edition it was.
gollark: (this was purchased by accident)
gollark: I could read my Scots copy of Harry Potter and the Philosopher's Stone without significant difficulty.
gollark: But they could *understand* it, presumably.

References
  • Fessler, Jennifer L. & Westneat, Mark W. (2007): Molecular phylogenetics of the butterflyfishes (Chaetodontidae): Taxonomy and biogeography of a global coral reef fish family. Mol. Phylogenet. Evol. 45(1): 50–68. doi:10.1016/j.ympev.2007.05.018 (HTML abstract)
  • FishBase [2008]: Chaetodon quadrimaculatus. Retrieved 2008-SEP-01.
  • Hsu, Kui-Ching; Chen, Jeng-Ping & Shao, Kwang-Tsao (2007): Molecular phylogeny of Chaetodon (Teleostei: Chaetodontidae) in the Indo-West Pacific: evolution in geminate species pairs and species groups. Raffles Bulletin of Zoology Supplement 14: 77–86. PDF fulltext
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